A glass panel unit including two or more glass panels stacked with a space therebetween to form a hermetically closed space and a vacuum created in the hermetically closed space is known (see, for example, Patent Literature 1). Such a glass panel unit is also referred to as an “insulated glazing”. Such a glass panel unit is also referred to as a “vacuum insulated glass”. The glass panel unit has high thermal insulation. In the glass panel unit, maintaining the vacuum is important.
It has been proposed that spacers be used to maintain a sufficient thickness for a vacuum space of such a glass panel unit. The spacers are parts interposed between the two glass panels.
In the glass panel unit, the spacers conduct heat between the two glass panels and thus influence the thermal insulation property of the glass panel unit. It is therefore desirable to reduce as much as possible the thermal conductivity of the spacers in a counter direction in which the two glass panels face each other.